import java.util.Scanner;
public class test11 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入一个开始数：");
        int fist = sc.nextInt();
        System.out.println("请输入一个结束数：");
        int last = sc.nextInt();
        int sum = 0;
        int i = fist;
        while (i <= last) {
            i++;
            if (i % 2 == 0) {
                sum++;
            }
        }
        System.out.println("符合条件的数有："+sum+"个");
    }
}
